Examples of known molding systems are (amongst others): (i) the HYPET (TRADEMARK) Molding System, (ii) the QUADLOC (TRADEMARK) Molding System, (iii) the HYLECTRIC (TRADEMARK) Molding System, and (iv) the HYMET (TRADEMARK) Molding System, all manufactured by HUSKY INJECTION MOLDING SYSTEMS LIMITED (location: Ontario, Canada).
Known insulating materials (also called “heat insulators”) are placed or located between components of known hot-runner systems, such as: a hot-runner manifold and a cooled mold plate. The following are examples of known heat insulators that are used in known hot-runner systems: asbestos, mica, ceramic, mineral wool, calcium silicate, and/or magnesium silicate, each example having a thermal conductivity that is greater than (sometimes as much as ten times more than) the thermal conductivity of air. It will be appreciated that these types of known heat insulators are relatively inefficient in comparison to using an air gap between the known components. The air gap is also a known heat insulator, but unfortunately the air gap permits the following drawbacks: (i) heat convection between the known components, and (ii) heat radiation transmitted between the known components when the known components are operated at respectively different temperatures. The following references provide examples of known heat insulators used in known hot-runner systems.
U.S. Pat. No. 2,878,515 (Inventor: STRAUSS; Published: 24 Mar. 1959) discloses an injection molding apparatus in which a molding material is injected into a heated chamber from which the molding material is passed to a cooled die cavity. The die cavity is insulated from the heated chamber by a heat insulator.
U.S. Pat. No. 3,231,656 (Inventor: NINNEMAN; Published: 25 Jan. 1966) discloses a molding apparatus having a section that includes a main feed block being heated by conduits separated from a platen by heat-insulating pads. The heat-insulating pads include TRANSITE™, which is a heat insulating material manufactured by JOHNS-MANVILLE COMPANY (location: United States of America).
U.S. Pat. No. 3,741,704 (Inventor: BEASLEY; Published: 26 Jun. 1973) discloses a hot-runner injection molding apparatus, which includes a plunger for injecting a molding material from a nozzle portion into a mold cavity of a mold that defines the shape of the article to be molded. A thermal insulator is used for insulating the nozzle portion from the mold.
U.S. Pat. No. 5,569,475 (Inventor: ADAS et al.; Published: 29 Oct. 1996) discloses a thermal-plastic molding device, which includes a thermal insulator provided between a nozzle assembly and surrounding plates. The thermal insulator includes a ceramic material such as zirconia oxide, which is sprayed to form a coating. Alternatively the thermal insulator can be provided as a ring around the nozzle assembly.
United States Patent Application Number 2004/0234644 (Inventor: PENG; Published: 25 Nov. 2004) discloses a molding machine, which includes: (i) an upper board connected to a material injection device, and (ii) a runner base connected to an underside of the upper board. The runner base includes a heat-isolating board and a scrap-removal board connected to the heat-isolating board. A plurality of runners is defined through the heat-isolating board.
United States Patent Application Number 2008/0069918 (Inventor: RAMOND; Published: 20 Mar. 2008) discloses, all around the peripheral edge of a distributor used in a molding system, a continuous peripheral space, which defines an air gap that contributes to the thermal insulation of the distributor. Thermal insulation is improved by filling the space with a thermal-insulating material.